This invention relates generally to improvements in and to a composite rectifying charge storage device of the type having a rectifier and capacitor which share common elements, as described in U.S. Pat. No. 6,414,543 and U.S. Publication US 2002/0140500 A1. More particularly, this invention relates to an improved composite rectifying charge storage device having an integrated bi-stable state responsive to an input signal for changing to one of two definable stable states, or vice versa. The bi-stable state may be irreversible or reversible.
U.S. Pat. No. 6,414,543 and U.S. Publication US 2002/0140500 A1, which are incorporated by reference herein, disclose embodiments for a rectifying charge storage element and related electronic circuits suitable for fabrication on various substrates, including flexible substrates, by various means including printing or other deposition techniques using organic conductors, semiconductors and insulators and other electronic materials suitable for deposition and use in electronic circuits. This rectifying charge storage element is disclosed for use as a power supply that extracts DC power (voltage and current) sufficient to power an electronic device from an AC input signal. The AC input signal may be derived from an inductive, capacitive, or L-C resonant circuit coupled to external AC electromagnetic field or electrostatic AC field. The electronic circuit thus powered may comprise a radio frequency identification (RFID) circuit.
In this regard, most electronic circuits require a source of DC voltage with sufficient current output to power the circuit elements. Many of these circuits derive DC power by rectifying and filtering an AC power signal. Often, the AC signal is provided to the circuitry by electromagnetic coupling. For example, a passive RFID tag system must be capable of receiving power from an RFID reader to the RFID tag via an inductive (H-field) or electric field (E-field) coupling, and transmitting data from the tag to the reader also via inductive or electric field coupling. The activation field frequency for typical RFID devices may range from less than about 100 kHz up to more than about 30 MHz if inductive or capacitive coupling is utilized, and up to the UHF and microwave region if electric field RF antenna coupling is used. In current industry practice, operating power to a passive RFID tag or other electronic circuit is derived by utilizing a rectifier device and a charge-storage device, typically a rectifier diode or combination of diodes connected to a charge storage capacitor or combination of capacitors. In the past, these elements have been implemented as separate components within a discrete circuit or silicon integrated circuit. See, for example, U.S. Pat. No. 4,333,072.
Recent advancements in circuitry manufacturing processes, applicable to RFID tag and similar electronic circuit systems, have enabled the production of electronic circuits on flexible substrates using thin film materials such as organic and polymer semiconductors and other substances that can be applied by techniques such as ink jet printing. A primary objective is to produce electronic devices that have operating characteristics similar to discrete or integrated silicon circuit technology sufficient to operate certain types of circuits while approaching the economy of printing processes. See, for example, U.S. Pat. Nos. 5,973,598 and 6,087,196.
The composite rectifying charge storage device disclosed in the above-referenced U.S. Pat. No. 6,414,543 and U.S. Publication US 2002/0140500 A1 incorporates a rectifier component such as a rectifying diode in combination with a charge storage component such as a capacitor, wherein these components share one or more common elements resulting in a composite device that is particularly suited for economical manufacture as by printing processes or the like. In addition, the composite device in especially suited for support on a flexible substrate which may comprise an integral portion of the device. Moreover, the supporting substrate may also comprise an electrically operative portion of the device. However, this rectifying charge storage device has many uses in electronic circuitry other than as a power supply device.